Commercial and industrial energy storage primarily focuses on peak shaving and valley filling, supported by demand control strategies and anti-backflow protection. However, differences in the number and capacity of station transformers, as well as diverse requirements for EMS in demand control and anti-backflow protection, lead to varied needs. For example, in scenarios with multiple grid connection points, demand protection may be applied to certain transformers while anti-backflow is implemented for the main transformer. Alternatively, in industrial parks with installed photovoltaic (PV) systems, EMS may require coordinated control of PV and storage. This article introduces corresponding control strategies for specific scenarios.
Case Scenario 1
1.1 Scenario Description
Only a single transformer’s load is considered, with multiple energy storage cabinets connected downstream of this transformer.
1.2 Control Strategy
Pure energy storage for peak-valley arbitrage + low-voltage anti-backflow (+ demand management).
1.3 Operation Mode
(1) The equipment operates in low-voltage grid-connected mode, charging during off-peak/flat periods and discharging during peak/sharp peak periods to capitalize on price differentials.
(2) A CT is installed at the low-voltage side for real-time load monitoring, enabling low-voltage anti-backflow to ensure self-consumption of stored energy within the factory premises.
(3) If billing is based on demand, the sum of the energy storage charging power and user load power must not exceed the set demand threshold.
Note: If the maximum charging power of the storage system plus the maximum load power exceeds the transformer capacity (which can be avoided during preliminary design), a demand limit can be set to prevent transformer overload.
Case Scenario 2
2.1 Scenario Description
The factory area has multiple (N) transformers, and energy storage systems are distributed across some (≤N) of them. The discharge of energy storage must account for all electrical loads in the factory, so anti-backflow protection must be implemented at the high-voltage 10 kV side.
Note: No more than 15 energy storage cabinets are allowed.
2.2 Control Strategy
Pure energy storage for peak-valley arbitrage + high-voltage anti-backflow (+ demand management).
2.3 Operation Mode
(1) The equipment operates in multi-point low-voltage grid-connected mode, charging during off-peak/flat periods and discharging during peak/sharp peak periods to capitalize on price differentials.
(2) A CT is installed at the high-voltage side for real-time current monitoring, enabling high-voltage anti-backflow to ensure self-consumption of stored energy across the entire factory area.
(3) If the park is billed based on demand, a maximum demand threshold must also be set.
If dynamic capacity expansion of transformers and overload prevention are considered, a GM330 power meter should be added under each transformer to achieve transformer overload prevention and dynamic capacity expansion.
Case Scenario 3
3.1 Scenario Description
A PV-storage scenario under a single transformer where neither PV nor storage systems can feed power back to the grid. PV inverters and integrated storage cabinets are connected to a communication box via RS485 cables and RJ45 network cables, respectively. Meanwhile, the SEC3000C is connected to three meters & CTs, deployed at the PV grid connection point (CT2), energy storage grid connection point (CT3), and transformer low-voltage side monitoring point (CT1).
3.2 Control Strategy
PV-storage coordinated control strategy.
3.3 Operation Mode
(1) PV generation prioritizes supplying the load. Excess power not consumed by the load charges the storage system. Any further excess is limited by curbing PV output. When PV generation is insufficient, the storage system discharges to supply the load. At night when PV is inactive, the storage system discharges to supply the load, with the grid supplementing as needed.
(2) During the day, when the load is high, only a small portion of PV power can charge the storage. Additional fixed-time charging can be applied at night (when electricity prices are lower), with configurable charging rates and cutoff SOC levels.
Summary
Energy storage control strategies are key to unlocking the potential of energy storage systems. Their development level directly impacts the effectiveness and adoption of energy storage technologies. In the future, with continuous technological advancements and expanding application scenarios, energy storage control strategies will evolve toward greater intelligence, precision, and coordination, providing robust support for building a clean, low-carbon, safe, and efficient energy system.
Post time: Jul-11-2025